Telephony.



E. R. GORWIN.

TELEPHONY.

APPLICATION FILED JUNE 15. 1909.

1,055,988. Patnted Mar. 11, 1913.

useful Improvement in Telephony, of which in which of-its casing beingabsent) made in accord-' ance with the preferred embodiment of the theexchange is connected with the line exis located. I have illustrate amenn. QORWIN, or

CHICAGO, ILLINOIS.

TELEPHONY;

Specification of Letters Patent.

Patented Mar. 11, 1913.

To 'aZZ whom. it. may concern:

Be it known that I, ELMER R. CORWIN, citizen. of the United States,residing at Chicago, in the county of Cook and State of Illinois, haveinvented a certain new and the following is a full, clear, concise, andexact description, reference beinghad to the accompanying drawings,forming a part of this specification.

My invention relates to telephony, and hasfor one of its objects theprovisi of a. telephone exchange system wherein the common battery maybe employed f0 energizing the receivers at sub-stations whe thelines areunited in conversation. r

I will explain my invention very fully by reference to the accompanyingdrawing,

Figure 1 is a diagrammatic view illustrating a telephone exchange systemequipped in accordance with the preferred embodiment of the invention.Fig. 2 is a longitudinal sectional view of a receiver (a part invention.Fig. 3 is a plan View of a plate adapted to be secured with respect tothe receiver casing. Fig. iis a view showing the electro-ma'gnetstructure, one of the plates shown in Fig. 3 being absent Fig. 5 is anelevation showing the assembly of the structures illustrated in Figs. 3and 4. Fig. 6 is a plan View of the structure shown in Fig. 5.

Like parts are indicated by similarv characters of reference throughoutthe differentfigures.

I have illustrated metallic circuit telephone lines, but it is to beunderstood that. the invention may be employed with grounded lines. V

The sides 1 and 2 of each telephone line illustrated extend to theexchange, where they are connected with the tip and sleeve contacts 3, 4of a jack switch. At each of the substations I have illustrated a transmitter 5, which is preferably included serially in the line between thesides thereof, battery current being supplied to the transmitterwhen'the cord circuit illustrated at tending to the station wherethetransrnitter at the exchange a plug 6 and a common battery 7, whichcommon battery is shown connected Application filed Jane 15, 1909.Serial No. 502,243.

in a conventional manner between the sides of the cord circuit for thepurpose of sup plying the transmitter with current as; stated. I havenot indicated at the exchange .any signaling apparatus, nor any of theoperators telephonic apparatus, as these are:

so well known as not'to require illustration.

I have shown my improved receiver 8 at each telephone sub-station, andwillfirst de- -scribe the circuit relation thereof in connection withFig. 1 and will thereafter describe the structural character-isticsthereof in. connection with the remaining figures.

This telephone receiver does not have a permanently magnetized core,but, instead, has a readily-magnetlzable and demagnetizable iron corewhich is formed to present its polar ends to the receiver diaphragm, the

polar ends of the core carrying the voice current windings 9 and 10,which are in parallel relation with each other and to-- 'gether are inserial relation with the line and the transmitter, these voice currentwindings performing the double function of energizing the core of thereceiver due to the passage of direct current from the battery 7 throughsaid windings and also being responsive to voice currents passed overthe lines, the windings 9 and 10 being wound to present little impedanceto the voice currents but being of sufficiently low resistance .topermit of the proper transmission of current from the common battery,the ohmic resistance of each of the windings being preferably fiftyohms. The windings 9 and 10 are so related to each other and to thecommon battery, that they will so magnetize the core of the receiver asto cause one pole of saidcoreto have a positive sign and the other poleof said core to have a negative sign. The joint resistance afforded bythese windings is thus equal to one-half of the .resistance that ispresented by each winding alone. By this arrangement, therefore, I amenabled to secure a receiver which is well adapted torespond to incomingtelephonic currents and which at the same timeis well adapted to permitof the transmission of current from the energizing source 7 through thereceiver, for the purpose of energizing it, and through the transmitter5,

. for the purpose of supplying the same with operating current, haveillustrated at each telephone station a switch-hook 11 havng an uppercontact -for including the re ceiver and transmitter in serial relationwith the line when the switch-hook is relieved of the weight of thereceiver and for including the'signal bell 12 and condenser 13 in bridgeof the line when the switch-hook supports the receiver. I

I will now describe the improved structural characteristics of thereceiver of my the same magnetic circuit and are spread apart at theirpolar ends in order to perinit of the disposition of the windings 9 10about said polar ends. In this feature of my invention, the coreportions are preferably formed of soft metal, but inasmuch as thisfeature of my invention is of a structural nature, I do not wish to belimited to the use of soft iron for the core portions. The polarportions of the receiver core are notched at 14 just back of the polarfaces of the core and in front of the voice coils 9 10.

A shallow pan 15 has its base provided with two apertures 16 that areshaped at their outer sides 17'to permit the polar portions of thereceiver to pass therethrough and are shaped at their inner sides 18only to receive the portions ,of the polar extremities of the core thatare reduced by the notches at 14 the'height of the notches at 14: beingsuch as to correspond with the thipkness of the pan 15, so thatethebottom of said pan may he slipped into said noiches when the pan bottomis brought into register with sa d notches. In assembling the parts, theportions of the core are engaged with" the pan bottom in the mannerwhich has been described, whereafter the portions formin the core areclamped together, whereby the pan 15 and the core of the receiver arevery firmly in terlocked. The rim of the pan 15 is suiii- (ientlyelevated from. the bottom thereof as to permit tlc diaphragm 19 to restwithin operative range of the polar faces of the core portion it. Thepan is fastened to some suitable form of easing, such as thatillustrated at 20. By the arrangement which I have described, the voicecoils are upon one side of the pan and the polar projections of thereceiver core are upon the other side of the pan. \Vhen the pan bott mand the core are to be interlocked, a filative lateral movement isbrought about between the core and the pan bottom, a reverse lateralmovement permitting of the disengagement oft'he pan bottom and core.

The conductors which lead to the voice current winding are provided eachwith a terminal 21 formed preferably out of thick strip brass, theseterminals, in turn, being connected with the joint terminals of thereceiver coils. These terminals are disposed between two strips ofinsulation 22 which have interlocking connection with the terminals toprevent movement of the terminals withrespect to the strips ofinsulation when the strips of insulation and the terminals areassembled. The core of the receiver is disposed-between the strips ofinsulation and a single fastening screw 23 is passed through the coreand the strips of insulation and serves to bind the core, the strips ofinsulation and the terminals in fixedrelation.

While I have herein shown and particularly described the preferredembodiment of my invention, I do not wish to be limited to the preciseconstruction and arrangement set forth, as changes may readily be madewithout depart-ing'from the spirit of the invention. 1

Having thus described my invention, I claim as new and desire to secureby Letters Patent the following z- 1. A telephone system including atelephone line extending between a telephone station and an exchange, asource ofdirect current at the exchange for supplying cur-. rent to thetelephone line, the telephone receiver at said station including areadily magnetizable and demagnetizable core and having two voicecurrent windings each of low impedance and in parallel relation witheach other and in serial relation with the line and both adapted to betraversed by telephonic current and thereupon cooperating to operate thereceiver and both being also adapted to be traversed by direct currentfrom said source of direct current to magnetize the core of thereceiver, the transmitter at said telephone station being in serialrelation with the line and the two voice current windings takentogether, whereby said transmitter may also be supplied with directcurrent from said source of direct current.

2. A telephone system including a telephone line extending between atelephone station and an exchange, a source of direct current at theexchange for supplying current to the telephone line, the telephonereceiver at said station including two voice current windingscach of lowimpedance and in parallel relation with each other and in serialrelation with the line and both adapted to be traversed by telephoniccurrent and thereupon cooperating to operate the receiver and both beingalso adapted to be traversed by direct current from said source memes ofdirect current to energize the receiver,

the transmitter at said telephone station beceiver at said stationincluding a readily magnetizable and demagnetizable core and having twovoice current windings each of low impedance and in parallel relationwith each other and in serlal relation with the both adapted to1betraversed by line an I telephonic current and thereupon ccoperat' ing tooperate the receiver and both being also adapted to be traversed'bydirect current from said-source of direct current to magnetize the coreof the receiver.

4..A telephone system including a telephone line extending between atelephone station and an exchange,a source of direct current at theexchange for supplying current to the telephone line, the telephonereceiver at said station including two voice current windings each oflow 1m edanoe' and 1n parallel relation wlth each 01: er and in serialrelation with the'line and both adapted to be traversed by telephoniccurrent and thereupon cooperating to operate the receiver and both beingalso adapted to be traversed by direct current from said source ofdirect current to energize the receiver.

5. A telephone system including a telephone line extending between atelephone station and a source of direct current, the

telephone receiver at said station including a readily magnetizable anddemagnetizable core and having two voice current windings each of lowimpedance and in parallel relation with each other and in serialrelation with the line and both adapted to be traversed by telephoniccurrent and. thereupon cooperating to operate the receiver and bothbeing also adapted to be traversed by direct,

current from said source of direct current to magnetize the core of thereceiver, the transmitterat said telephone. station being in serialrelation with the line and the two voice ,current windings takentogether, whereby said transmitter may also be supplied withdirectcurrent from said source of direct current.

6. A telephone system includinga tele' phone line extending between atelephone station and a source of direct current, the

telephone receiver at said station including two voice current windingseach of low impedance and'in parallel relation with each other and inserial relation with the line and bothadapted to be traversed bytelephonic current and thereupon cooperat-' ing to operate the receiverand both being also adapted to be traversed by direct current from'saidsource of direct current to energize the receiver, the transmitter atsaid telephone station, being in serial relation with the line and thetwo voice current windings taken together, whereby said transmitter mayalso be supplied with direct current from said source of direct current.7. A telephone system including a telephone line extending between atelephone station and a source of direct current, the telephone receiverat said station including a readily magnetizable and demagnetizable'core and having two voice current windings each of low impedance and inparallel relation with each other and in serial relation with the lineand both adapted to be traversed by telephonic current and thereuponcoiiperating to-operate the receiver and both being also adapted to betraversed by direct current from said source of direct current tomagnetize the core of the receiver.

8. A telephone system including a telephone line extending between atelephone station and a source of direct current, the telephone receiverat said station including two voice. current windings each of lowimpedance and in parallel relation with each other and in serialrelation with the line a and both adapted to be traversed by telephoniccurrent and thereupon cooperating to operate the receiver and both beingalso adapted to be traversed by direct current from said sourceof directcurrent to ener-- gize the receiver.

9. A telephone system -including a telephone line extending-between atelephone station and an exchange, a'source of direct current attheexchange for supplying current to the telephone line, the telephonereceiver at said station including a readily rnagnetizable and.demagnetizable core and having two windings in arallel relation witheach other and in serial relation with tlte'line at least one of saidwindings being traversed by telephoniccurrent and both being adapted tobe traversed bydirect current from said source of direct current tomagnetize the, core of the receiver, the transmitterat said telephonestation being in .se-

rial relation with the line and the two windings taken together, wherebysaid transmitter may also beisupplied with direct current from saidsource of direct current.

10. Atelephone systemincluding a telephone line extending between a.telephone station and an exchange, a source of. direct current at theexchange for supplying current to the telephone line, the telephonereceiver at said station including two wind- -ings in parallel relationwith each other and-in serial relationiwit-h the line at least I &

one of said windings being adapted to be traversed by telephonic currentand both being adapted to be traversed by direct current from saidsource of direct current to energize the receiver, the transmitter atsaid telephone station being in serial relation with the line and thetwo windings taken together, whereby said transmitter may alsobesupplied with direct current from said source of direct. current.

11. A telephone system including a telephone line extending between atelephone station and an exchange, a source of direct current at theexchange for supplying current to the telephone line, the telephonereceiver at said station including a readily magnetizable anddemagnetizablecore and having two windings in parallel relation witheach other and in serial relation with the line at least one of saidwindings being adapted to be traversed by telephonic current and bothbeing adapted to be traversed by direct current from said source ofdirect current to inagnetize the core of the receiver.

12. A telephone system including a telephone line extending between atelephone station and an exchange, a source of direct current at theexchange for supplying current to the telephone line, the telephonereceiver at said station including two windings in parallel relationwith each other and in serial relation with the line at least one ofsaid windings being adapted to be trav ersed by telephonic current andboth being adapted to be traversed by direct current from said source ofdirect current to energize the receiver.

13. A telephone system including a telephoneline extending between atelephone station and a source of direct current, the telephone receiverat said station including a readily magnetizable and demagnetizable coreand having two windings in parallel relation with each other and inserial relation with the-line atleast one of said windings being adaptedto be traversed by telephonic currentand both being adapted to betraversed by direct current from said source of direct current tomagnetize the core of the receiver, the transmitter at said telephonestation being in serial relation with the line and thetwo windings takentogether, whereby said transmitter may also be supplied with directcurrent from said source of direct current.

14. A telephone system including a tele phone line extending between atelephone station and a source of direct current, the telephone receiverat said station including two windings in parallel relation with eachother and in serial relation with the line at least one of said windingsbeing adapted to be traversed by telephonic current and both beingadapted to be traversed by direct current from said source or directcurrent to energize the receiver, the transmitter at said telephonestation being in serial relation with the line and the two windingstaken together, whereby said transmitter may also be supplied withdirect current from said source of direct current.

15. A telephone system including a telephone line extending between atelephone station and a source of direct current, the telephone receiverat said station including a readily magnetizable and demagnetizable coreand having two windings in parallel relation with each other and inserial relation with the line at least one of said windings beingadapted to be traversed by telephonic current and both being adapted tobe traversed by direct current from said source of direct current tomagnetize the core of the receiver.

16. A telephone system including a telephone line extending between atelephone station and a source of direct current, the

telephone receiver at said station including phone line extendingbetween a telephone station and-an exchange, a source of direct currentat the exchange for supplying current to the telephone line, thetelephone receiver at said station including a magnetizable core andhaving two circuits in parallel relation with each other and in serialrelation with the line and both adapted to be traversed by current fromsaid source of direct current, and each including a winding serving tomagnetize the receiver core, due to the passage of the direct current,one of said windings serving to permit of the passage of voice currents,the transmitter at said station being in serial relation with thecircuits of the receiver taken together, and thereby being adapted to besupplied also with current emanating from the source of direct current.

18. A telephone system including a telephone line extending between atelephone station and an exchange, a source of direct current at theexchange for supplying current to the telephone line, the telephonereceiver at said station having two receiver energizing circuits inparallel relation with each other and in serial relation with the lineand both adapted to be'traversed by direct current from said source ofdirect current, to energize the receiver, one of said windings servingto permit of the passage of voice currents, the transmitter at saidstation .being-inserial relation with the circuits of the receiver takentogether, and thereby being adapted to be supplied also with currentemanating from the source of direct current. i

19. A telephone system including a tele phone line extending between atelephone station and an exchange, a source of direct current at theexchange for supplyingcurrent to the telephone line, the telephone receiver at said station including a magnetizable core and having twocircuits in parallel relation With each other and in serialrelm tionwith the line and both aolaptetl to be traversed by current from saidsource of direct current, and each including a Winding serving tomagnetize the receiver core, clue to the passage of the direct current,one of said windings serving to permit of the pas-- sage of voicecurrents.

20. A telephone system including a telephone line extending between atelephone station and an exchange, a source of direct current at theexchange for supplying current to the telephone line, the telephonereceiver at said station having two receiver, energizing circuits inparallel relation with each other and in serial relation with the lineand both adapted to be traversed by clirect current from said source ofdirect current to energize the receiver, one of said windings srving-topermit of the passage of voice currents In Witness whereof, Ihereunto subscribe my name this 14th. day of JuneA. I1, 1909.

ELMER COEWIN.

Witnesses L. Gm S'rnon, G. L. Cease.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents.

Washington, D. C.

